1. Field of the Invention
The present invention relates to a touch pad which is mounted on a notebook PC and the like.
2. Description of the Related Art
In recent years, there has been a tendency for touch pads mounted on a notebook PC and the like to be increased in size. However, in a case of the increase in size of the touch pad, there is a tendency for a touch of a palm to be performed when operating a keyboard, and thus an operational error is likely to occur. The present invention relates to means for preventing the operational error (palm determination function or palm rejection function).
U.S. Unexamined Patent Application Publication No. 2009-0095540 discloses that the determination of whether being a finger or a palm is performed on the basis of spatial characteristics such as an area, shape, and the like of a touch region and that an operation is set to be in an invalid state when being determined to be a palm. Accordingly, it is possible to prevent an operational error from occurring due to a palm. However, when spatial characteristics of a touch region when being touched by a finger are similar to those when being touched by a palm, it may be determined that a touch is caused by a palm in spite of the touch being caused by a finger, and thus an operation may be set to be in an invalid state. Thus, there is a problem in that it is not possible to smoothly perform a normal operation by a finger.